Rapid development of industry causes modern people to consider a house not only as a residential space, and technologies are proposed to provide convenience to residents at home. Generally, a television set is placed in a living room where the residents spend a lot of time. However, the majority of modern daily family life is spent in a kitchen where meals are had. Particularly, housewives, who spend most of their daily working time in the kitchen, are interested in technologies that can make their work in the kitchen more convenient. Television sets and audio sets attachable to wall cabinets in kitchens have been developed so that housewives or housekeepers can view broadcast programs and listen to music through the television sets and the audio sets even when they are working in the kitchen.